Various hand operated instruments exist for use by dentists, endodontists and other medical professionals. For example, during root canal procedures, dental pulp is removed in the area of the root canals and the dentist or endodontist obturates the tooth by filling the hollow, enlarged canals with a suitable filler material and then sealing the tooth. This prevents further infection of the tooth and/or surrounding area. Typically, the root canal is obturated by injecting gutta percha or other material in a softened and highly viscous condition. The gutta percha then hardens within the enlarged and cleaned root canals, while also retaining some resiliency. Usually root canal filler materials are thermoplastic in that they are initially solid or semi-solid and become softened and extrudable after heating. Various other types of materials may be extruded or otherwise dispensed during dental, endodontic or other medical procedures. Such instruments may or may not have disposable compules or cartridges of the material which may be inserted into the device, heated just prior to use, and disposed of after the treatment.
Various needs for improvement exists in the area of medical devices that are hand-operated and, even more particularly, in the area of hand-operated dental and/or endodontic instruments that dispense materials. Such needs include, for example, manners to improve the ability to easily allow for sterilization and reuse of the device on different patients, the ability to efficiently and uniformly preheat a disposable cartridge or compule of material, and the ability to efficiently manufacture an effective single-use needle or cannula associated with the single-use cartridge or compule of material. These and other areas of improvement are addressed by the present invention.